An important issue in signal processing in hearing instruments is perception of the own voice by a hearing instrument user.
The own voice reaches the tympanic membrane via two different paths:                Air conduction: the main contribution as long as the ear canal is not occluded        Bone conduction: a significant contribution as soon as the ear canal is at least partially occluded.        
These two contributions undergo an acoustic summation in the ear canal before being perceived.
The naturalness and pleasantness of this perception among others may depend on three distinct aspects:                Occlusion (increased low-frequency contents of the bone conducted portions of the own voice)        Ampclusion (increased low-frequency contents of the hearing instrument sound, including the air-conducted portion of the own voice);        Individual preferences (users might have gotten used to an ‘unnatural’ (influenced by their hearing capabilities) perception of the own voice or prefer their own voice to sound differently, for example less squeaky, from what would be ‘natural’).        
In traditional hearing instruments, only the air conducted portion of the own voice can be affected by the processing (i.e. ultimately the frequency dependent amplification). A hearing instrument featuring active occlusion control can additionally affect—i.e. frequency-dependently decrease—the bone-conducted portion.
Even if the occlusion—especially the unwanted increase of low-frequency contents of the bone-conducted portion of the own voice—is fully removed by the active occlusion control, there is still a trade-off in terms of ampclusion. Specifically, the optimal setting of the hearing instrument gain in terms of ambient sounds might not be optimal in terms of the own voice.
In order to solve this problem, the state of the art proposes to detect own voice activity and to then, during own voice activity, temporarily change the hearing instrument settings so that they are optimal for the perception of the own voice.
WO 2004/021740 discloses such an example where an ear canal microphone is used to detect conditions leading to occlusion problems. EP 2 040 490 discloses approaches to detect ampclusion effect situations by a MEMS sensor. In order to account for the ampclusion effect and also for individual preferences, WO 03/032681 discloses to hold a training session in which the user may adjust parameters until the processed own voice is perceived as having a satisfying sound quality. The parameter values are stored and used when the own voice is detected.
However, the temporal change in the hearing instruments settings implies that the perception of ambient sounds is different while the user speaks than when he is quiet.
The state of the art does not propose any solution to this problem.